import org.junit.Test;

import java.security.PublicKey;
import java.util.Arrays;
import java.util.List;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public class StreamDemo {


    //创建Stream方式一：通过集合
    @Test
    public void test1() {
        List<Employee> employees = EmployeeData.getEmployees();

        //default Stream<E> stream(); ：返回一个顺序流
        Stream<Employee> stream = employees.stream();

        //default Stream<E> parallelStream(); ： 返回一个并行流
        Stream<Employee> parallelStream = employees.parallelStream();
    }

    //创建Stream方式二：通过数组
    @Test
    public void test2() {
        int[] arr = new int[]{1, 2, 3, 4, 5, 6};
        //调用Arrays类的static<T> Stream<T> stream(T[] array): 返回一个流
        IntStream stream = Arrays.stream(arr);

        Employee e1 = new Employee(1001, "Tom", 12, 100.1);
        Employee e2 = new Employee(1002, "Jerry", 12, 100.1);
        Employee[] arr1 = new Employee[]{e1, e2};
        Stream<Employee> stream1 = Arrays.stream(arr1);
    }

    //创建Stream方式三： 通过Stream的of()
    @Test
    public void test3(){
        Stream<Integer> stream = Stream.of(1, 2, 3, 4, 5, 6);
    }

    //创建Stream方式四：创建无限流
    @Test
    public void test4(){

        //迭代
        //public static<T> Stream<T> iterate(final T seed,final UnaryOperator<T> f)
        //遍历前10个偶数
        Stream.iterate(0,t->t+2).limit(10).forEach(System.out::println);

        //生成
        //public static<T> Stream<T> generate(Supplier<T> s)
        Stream.generate(Math::random).limit(10).forEach(System.out::println);
    }


}
